In urban areas, sewage discharge is the major contributor to water pollution. Untreated or improperly treated sewage releases harmful bacteria, viruses, and parasites into water bodies, posing significant health risks.

Agricultural activities often involve the use of pesticides to control pests and enhance crop yields. These pesticides can contaminate water sources through runoff, posing risks to aquatic life and human health.

Heavy metals, such as lead and mercury, can accumulate in the body over time and cause neurological disorders. These metals can impair cognitive function, cause developmental issues in children, and increase the risk of neurodegenerative diseases.

Giardia is a protozoan parasite that can contaminate water sources and cause gastrointestinal illnesses. Symptoms of giardiasis include diarrhea, abdominal cramps, nausea, and vomiting.

Microplastics are tiny plastic particles that can enter water bodies from various sources. These particles can accumulate in the body and disrupt the endocrine system, potentially leading to hormonal imbalances and reproductive problems.

Industrial activities often release heavy metals into the environment, which can contaminate water sources. These metals can pose significant health risks, including neurological disorders, kidney damage, and developmental issues.

Pharmaceuticals, such as antibiotics and hormones, can enter water sources through wastewater discharge. Consuming water contaminated with these substances can contribute to the development of antibiotic resistance, making it more difficult to treat bacterial infections.

Legionella is a bacterium that can contaminate water sources, particularly in warm and stagnant water. It can cause Legionnaires' disease, a severe form of pneumonia, and Pontiac fever, a milder respiratory illness.

Fecal coliform bacteria are indicators of fecal contamination in water. Consuming water contaminated with these bacteria can cause gastrointestinal illnesses, including diarrhea, vomiting, and abdominal cramps.

Stormwater runoff can carry various pollutants, including microplastics, into water bodies. These tiny plastic particles can accumulate in the environment and pose risks to aquatic life and human health.

Viruses, such as norovirus and rotavirus, can contaminate water sources and cause gastrointestinal illnesses. Symptoms of viral gastroenteritis include diarrhea, vomiting, and abdominal cramps.

Hepatitis A virus can contaminate water sources and cause hepatitis A, a liver infection. Symptoms of hepatitis A include jaundice, fatigue, nausea, and vomiting.

Bacteria, such as E. coli and Salmonella, can contaminate water sources and cause gastrointestinal illnesses. Symptoms of bacterial gastroenteritis include diarrhea, vomiting, and abdominal cramps.

Pseudomonas is a bacterium that can contaminate water sources, particularly in warm and stagnant water. It can cause eye and ear infections, as well as skin and respiratory infections.